The study is a Phase II, dose-ranging, multicenter, randomized, double-blind, placebo-controlled, parallel-group study of the efficacy and safety of a single subcutaneously administered omalizumab dose as add-on therapy for the treatment of adolescent and adult patients 12-75 years old who have been diagnosed with CIU and remain symptomatic despite treatment with therapeutic doses of an H1 antihistamine. The study will enroll approximately 76 patients at approximately 45 study centers in the United States and Germany.

The UAS is a composite diary−recorded score, which is the sum of the numeric severity intensity ratings (0 = none to 3 = intense) for 1) the number of wheals (hives) and 2) the intensity of the pruritus (itch). The UAS7 is the sum of the daily average UAS (morning and evening values) for 7 days. The maximum UAS7 score is 42.

Secondary Outcome Measures:

Change in the Weekly Pruritus Score From Baseline to Week 4 [ Time Frame: Baseline (based on the 7 days prior to randomization) and 4 weeks (Days 21-27) ] [ Designated as safety issue: No ]

The pruritus (itch) score was recorded by participants twice daily (morning and evening) based on the severity of itch over the last 12 hours, using a scale from 0 (none) to 3 (severe). The weekly pruritus score was the sum of average daily pruritus scores over the previous 7 days. The range of the weekly score is 0-21.

Change in the Weekly Score for Number of Hives From Baseline to Week 4 [ Time Frame: Baseline (based on the 7 days prior to randomization) and 4 weeks (Days 21-27) ] [ Designated as safety issue: No ]

The number of hives was recorded by participants twice daily (morning and evening) using a scale from 0 (no hives) to 3 (more than 12 hives). The weekly score of number of hives was the sum of the average daily scores over the previous 7 days, and ranged from 0 to 21

Change in the Weekly Score for Sleep Interference From Baseline to Week 4 [ Time Frame: Baseline (based on the 7 days prior to randomization) and 4 weeks (Days 21-27) ] [ Designated as safety issue: No ]

The extent to which hives or itch interfered with participants' sleep was recorded once daily in the patient diary using a scale from 0 (no interference) to 3 (substantial interference, waking often). The weekly score of sleep interference was the sum of the daily scores over the previous 7 days, and ranged from 0 to 21.

Change in the Weekly Score for the Amount of Rescue Medication From Baseline to Week 4 [ Time Frame: Baseline (based on the 7 days prior to randomization) and 4 weeks (Days 21-27) ] [ Designated as safety issue: No ]

Diphenhydramine 25mg was provided and used on an as-needed basis (maximum 3 times/day) as rescue medication. The weekly score for the amount of rescue medication is the sum of the daily scores for the amount of rescue medication used at each day in the week, and ranged from 0 to 21.

Number of Patients With Adverse Events by Severity [ Time Frame: 4 Weeks ] [ Designated as safety issue: No ]

The severity (i.e. intensity) of each Adverse Event (AE) was graded according to the following scale: Mild: Symptoms causing no or minimal interference with usual social and functional activities. Moderate: Symptoms causing greater than minimal interference with usual social and functional activities. Severe: Symptoms causing inability to perform usual social and functional activities.

Additional AE data is provided in the AE section below. The terms "severe" and "serious" are not synonymous. Severity refers to the intensity of an AE. A "Serious" AE is defined below.

Number of Participants With Immunogenicity [ Time Frame: 16 weeks ] [ Designated as safety issue: No ]

Omalizumab (Xolair) was administered subcutaneously on Day 0 of the study. Participants remained on stable doses of their pre-allocation Chronic Idiopathic Urticaria (CIU) H1 antihistamine treatment throughout the study, and were provided diphenhydramine as rescue medication for pruritus relief on an as-needed basis.).

Diphenhydramine was provided and used on an as-needed basis (25 mg per dose)

Experimental: Omalizumab 300 mg

Omalizumab (Xolair) was administered subcutaneously on Day 0 of the study. Participants remained on stable doses of their pre-allocation Chronic Idiopathic Urticaria (CIU) H1 antihistamine treatment throughout the study, and were provided diphenhydramine as rescue medication for pruritus relief on an as-needed basis.

Diphenhydramine was provided and used on an as-needed basis (25 mg per dose)

Experimental: Omalizumab 600 mg

Omalizumab (Xolair) was administered subcutaneously on Day 0 of the study. Participants remained on stable doses of their pre-allocation Chronic Idiopathic Urticaria (CIU) H1 antihistamine treatment throughout the study, and were provided diphenhydramine as rescue medication for pruritus relief on an as-needed basis.

Diphenhydramine was provided and used on an as-needed basis (25 mg per dose)

Placebo Comparator: Placebo

Participants received a single subcutaneous placebo injection on Day 0 of the study. Participants remained on stable doses of their pre-allocation Chronic Idiopathic Urticaria CIU) H1 antihistamine treatment throughout the study, and were provided diphenhydramine as rescue medication for pruritus relief on an as-needed basis.

Drug: omalizumab

Administered by subcutaneous injection

Other Name: Xolair

Drug: placebo

Participants received a single subcutaneous placebo injection on Day 0 of the study.

Patients may not take during treatment period or have been taking within the past 3 months any of the following medications/treatments: regular (daily/every other day) hydroxychloroquine, methotrexate, cyclosporine, cyclophosphamide, IVIG, or plasmapheresis

Patients may not have been taking doxepin within the past 6 weeks regular (daily/every other day).

Contacts and Locations

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study.
To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below.
For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT00866788